1. Field of the Invention
This invention relates to a chemical analysis film chip having a reagent layer whose optical density changes upon reaction with a specific biochemical component contained in a sample liquid such as blood or urine.
2. Description of the Prior Art
Quantitative or qualitative analysis of a specific component in a sample liquid is a common operation carried out various industrial fields. Especially, quantitative analysis of a chemical component or a solid component contained in body fluid such as blood or urine is very important in the field of clinical biochemistry.
There has been put into practice a "dry-to-the-touch" (to be expressed simply as "dry" hereinbelow) chemical analysis slide with which a specific component contained in a sample liquid can be quantitatively analyzed through a droplet of the sample liquid spotted onto the slide. See Japanese Patent Publication No. 53(1978)-21677, U.S. Pat. No. 3,992,158, Japanese Unexamined Patent Publication No. 55(1980)- 164356, U.S. Pat. No. 4,292,272 or the like. When such a dry chemical analysis slide is used, the sample liquid can be analyzed more easily and more quickly than when the conventional wet analysis method is used, and accordingly the dry chemical analysis slide is very convenient for medical facilities, laboratories and the like where lots of sample liquids have to be analyzed.
When chemical components or the like contained in a sample liquid is analyzed using such a dry chemical analysis slide, a droplet of the sample liquid is spotted onto the slide and is held at a constant temperature for a predetermined time (incubation) in an incubator so that coloring reaction occurs, and the optical density of the color formed by the coloring reaction is optically measured. That is, measuring light containing a wavelength which is pre-selected according to the combination of the component to be analyzed and the reagent contained in the reagent layer of the slide is projected onto the slide and the optical density of the slide is measured. Then the component to be analyzed is quantitatively analyzed on the basis of the optical density using a calibration curve which represents the relation between the concentration of the biochemical component and the optical density.
The chemical analysis slide comprises a dry chemical analysis film and a plastic frame which holds the chemical analysis film flat to facilitate handling of the film during transfer. The chemical analysis film is generally composed of a support sheet of plastic or the like and a reagent layer and a spreading layer superposed on the support sheet or of a support sheet and a water absorbing layer having hydrophilic polymer as a major component and a spreading layer containing therein a reagent which are superposed on the support sheet.
The chemical analysis slides are transferred to an incubator one by one after spotted with a sample liquid. Generally the incubator has a plurality of cells for accommodating the chemical analysis slides. Each cell is in the form of a slit (or a flat room) which opens in the side of the incubator and the chemical analysis slides are inserted into the cells. Such transfer of the chemical analysis slides can be done, for instance, by a reciprocating claw member as disclosed in U.S. Pat. Nos. 4,296,069 and 4,568,519 and the like. The frame facilitates transfer of the chemical analysis film.
However, use of such chemical analysis films with frame results in increase in the size of various parts handling the films such as cells in the incubator for incubating the chemical analysis films, the transfer system, a film supplier for storing the films in dry state and the like. Thus the frame of the chemical analysis film is obstructive to reducing the size of the biochemical analysis system and at the same time reduces the film accommodating capacity of the incubator, which obstructs increase in handling capability of the overall biochemical analysis system.
Further cost for mounting the frame is high, which adds to cost of biochemical analysis.